A size reduction of a compressor is required when low cost and ease of installation to a vehicle are concerned. Disposing a compression portion inside a drive motor is effective in reducing a size. PTL 1 discloses a compressor having a compression portion disposed inside a motor. PTL 1 discloses a compressor including a cylinder formed integrally with a rotor of an electric motor and a stationary piston provided eccentrically with respect to the cylinder. A compression chamber is formed between the cylinder and the piston using a vane portion (partition plate). The cylinder integral with the rotor is configured so as to rotate with respect to the piston in a stationary state, in comparison with a normal rolling piston. The cylinder integral with rotor, however, is fundamentally a normal rolling piston and therefore has a vane nose, which gives rise to a sliding loss. Because a spring and the vane are disposed to the rotating cylinder portion, a centrifugal force is exerted at high-speed rotation. When the centrifugal force becomes larger than the spring force, a clearance (fall-off of the vane) is generated between the vane nose and the rotor. In such a case, a compression operation is no longer performed and performance is deteriorated. Hence, PTL 1 is not suitable for a high-speed operation.
PTL 2 discloses a two-way rotary scroll compressor. An operation chamber can be formed in the two-way rotary scroll compressor without a vane. However, the cost increases due to precision work on a scroll in PTL 2. In addition, because a fixed scroll board of a typical scroll compressor is rotated, two scroll boards have to be supported in the manner of a cantilever. The scroll boards have unbalance and vibrate when rotated in the manner of a cantilever. In the case of a scroll compressor, a discharge port has to be provided at a center and the center serves as a shaft portion. Hence, the scroll compressor is configured in such a manner that a discharged high-pressure refrigerant passes through the rotating shaft portion. On the contrary, a drawing pressure on the periphery of the shaft portion is low. It is therefore difficult to seal the rotating shaft portion.